Crankshaft chuck



y 1941- w. F. GROENE ETAL 2,250,631

GRANKSHAFT CHUCK Filed Oct. 16, 1939 4 Sheets-Sheet 1 WITNESS. H: I INVENTOIRS.

$6 M WILLIAM FGROENE BY m gm. ER R.METER ATTORNEY.

July 29, 1941. w. F. GROENE ETAL CRANKSHAFT CHUCK 4 Sheets-Sheet 2 Filed Oct. 16,1959

E m o mu m W m WMR A UL L w j M w l* W u .E

WITNESS. lf l/ y 29, 1941 w. F. GROENE ETAL 2,250,631

CRANKSHAFT CHUCK I Filed Oct. 16, 1939 4 Sheets-Sheet z FTC- -111 WITNESS:- BY WALTE .$-1ETER V wJLSlML. A

y 9, 1941- w. F. GROENE ETAL 2,250,631

CRANKSHAFT CHUCK Filed Oct. 16, 1939 4 Sheets-Sheet 4 FTEY INVENTORS. wuum F. GROENE WALTER R. METER mmww, mM lam.

Patented July 29, 1941 CRANKSHAFT CHUCK William F. Greene and Walter E. Meyer, Cincinnati, Ohio, assignors to The R. K. Le Blond Machine Tool Company, Cincinnati, Ohio, a

corporation oi Delaware Application October 16, 1939, Serial No. 298,732 Claims. (Cl. 82-40) This invention pertains to chucking devices for machine tools and more particularly to chucking devices adapted to grip irregular pre-located work pieces in lathes and the like. More specially this invention pertains to the chucking and rotating of relatively long work pieces which are centered at each end and which must be supported and driven intermediate these ends as in a center drive lathe. This problem of driving rough irregular work pieces such, for example, as multi-throw crankshafts for internal combustion engines, is particularly difiicult because such work pieces are relatively limber and easily deflectable from true centered position in the lathe due to the relatively large amount of material which must be rapidly removed from such work pieces during the machining operations thereon.

It is therefore the primary object of this invention to provide a chucking device which will grip such an irregular pre-located work piece with great rigidity by means of its rough surfaces, while at the same time not distorting it from its true pre-located position while holding it solidly for properly supporting and driving it during the machining operations.

One object of this invention is to provide a chuck having a work engaging mechanism adapted to engage a rough irregular surface of a prelocated Work piece at a large number of circumferentially disposed points on the work piece and to lock this mechanism subsequently, after its complete'engagement with the work piece, to the chuck body whereby the work piece is positively held in accurate pre-locatedposition so that it may be powerfully driven during machining operations to be performed thereon.

Another object of this invention is to provide in a chucking device work engaging mechanism comprising substantially a chain of work engaging links adapted to be wrapped around a rough irregular pre-located work piece to be gripped and to be tightened about said work piece to engage it at a multiplicity of points. Andthen it is our object to subsequently lock this work engaging mechanism, after it has been fully engaged With the work piece, to the chuck body in such a manner as not to cause dislocation of the work piece from its pre-located position while at the same time providing means whereby this work engaging portion is rigidly locked to the body of the chuck.

Another object of this invention is to provide a unique locking mechanism which floats to locking position as predetermined'by the work piece engaging the work engaging members of the chuck but which, when finally locked up forms a solid and rigid abutment preventing all further movement of the work engaging members of the chuck relative to the chuck body so that the work piece is positively and rigidly held in accurate pre-located position during the ma- .chining operation to be performed on the Work Further features and advantages of this invention will appear in the following detailed de-. scription of the drawings in which:

Fig. I is a view axially of a chucking device incorporating the features of this invention show ing the chuck fully engaged on a pre-located rough irregular work piece in the chuck.

Fig. II is a similar axial view of the chucking device of Fig. I but showing the chuck disengaged from the work piece illustrating the position of the various chucking members at the time of insertion or removal of the work piece therefrom.

Fig. III is an enlarged section of the locking device on the line IIIIII of Fig. I showing it withdrawn from looking position at the time of initial engagement of the work engaging mechanism with the-work piece.

Fig. IV is a transverse section throu'glrthe locking plungers substantially on the linelIVIV of Figs. III and V. c

Fig. V is an enlarged section similar to that of Fig. III but showing'the relative position of .the locking plunger inserted into the abutment .bore of the chuck body at the time of final looking of the work engaging mechanism with the chuck body for rigidly supporting and driving the work during the turning operation.

For purposes of an exemplary disclosure this invention is shown applied to a machine tool work spindle comprising a ring gear I of a center drive crankshaft lathe and comprises a segmental member 2 which is securely fixed to the bore ,3 of this ring gear by means of the key 4 and suitable bolts 5. The work engaging member of this chucking device comprises a plurality of links 6, 1, 8, 9, ill and II, link 6 being connected to link II' by a pin I2, link being connected to link ii) by a pin I3, while link 1 is pivotedly mounted on link 8 by a pin l4 and the link- 9 being connected to the link 8 by a pin IS, the links 9 and in being connected together by a common pin it. Thisentire asse'mbly'oflinks is connected pivotedly to the chuck body through a link I! which is pivotedly connected at one end about the common pin I6 above mentioned and pivotedly mounted in the segmental member 2 on a pin l8.

The link 8 has work engaging abutments l9 and and the link H) has work engaging abutments 2| and 22 and the adjustable abutment 23 comprising a set screw 24 threaded at 25 in the link it) and passing through an appropriate clearance "hole 26 in the pin I6. The link i5 has the work engaging abutment 21 and the movable clamping abutment or plunger 28 which may be moved axially in and out in the bore 29 of the link 6 by means of the actuating screw 3! which is axially confined in the link 6 by appropriate bearing'means 6| *and has a threaded end 32 operating'in the threaded'bore 33 of the plunger 28. An appropriate socket 34 for a suitable wrench is provided in screw 3!! for rotating it one way orthe other. 'The link I has a threaded outer end 35, having a normally fixed adjustable square nut 36 which'may be entered in to the latchipocket 31 of "the link"8 so as to latch link thereto.

It will be apparent that whenthe screw is tightened by appropriately applying a wrench to the socket 34 and rotating itto force the plungr=28outwardly against the workpiece W, --the entire assembly "of links will be caused to tighten and "wrap themselves securely around the work piece, bringing all of the variousabutments 119,20, 2|, 22, 23,21 and 28 to firmly engage themselves "with substantially equal pressure on the Work surface. The abutment 23 is made adjustable for pu'rposesof assisting in'the 'initial orientation ofthe'chain of links relative to' the workWfor' best engagement'of the -various abutments therewith. 'The'link serves to substantially position this work engaging'mechani'sm comprising the assembly of this chain' of links for proper engagement with the workpiece W which has been pre-l'ocated'in the chuckbody "while 'at the same time permitting complete? freedom of floating movement of the-wo'r-kengaging assembly so that it may firmly engage itself on :the"work piece without distorting itfromits pre- "loca'te'd :position. The link however, does function to prevent rotation of this assembly relative to the chuck body when-- engaged on the "work in cooperation with the 'locking p'ie'ce for binding this assembly to the ichuck'bo'dy I, as will now be described.

After this work engaging assembly has been cla'mp'edbn the'wo'rkras described, the locking pl'urige'r38, bestshown in'Fig;III, is then moved axially in the bore'39 in" the link 6, so as to move -it to' the Tight asshown in "Fig. V tO bring the abutment plunger's 40 into the abutment 1 bore" '4 formed in theweb portion of the segmental piece 2 fixed 'in'the' ring-gear This is accomplished -byapplying the chuck wrenchpreviously applied to thesocket- 34 of the screw 30 to the of-the pinion shaft'lS appropriately journaled 'in the link 6*and having a'pinion'M-arra-nged to engage-the rack* cut "on the periphery ofthe locking'plunger iiii so that,'by rotating this shaft 43 the"plunge'r 38"may bemoved axially'in'the jb6r'e'39' for niov'in'g'the 'lo'cki'ng' plunger into or out of'the abutment boredl. "Itisobvioiis that after the clamping of the wor-k engaging assembly, comprising the series of links, has been tight ly -g ripped-on the work,the bores 39 and M do not necessarily accurately line up because of the rough irregularities of the workpiece affects the precise {engagement of various links with their Eabut'ment surfaces in any definite position-for socket 42 each crankshaft or work piece inserted in the chuck.

It is therefore necessary to have an equalizing locking mechanism to provide a positive locking pin between these two bores so as to prevent relative movement of the link and the chuck body after the initial engagement of the clamping mechanism on the work. Thus; after this plunge'r"38 has been axially moved'tdtheright, Fig. V, to bring the locking plunger 40 into the bore 4|, the wrench applied to the socket 46 of the locking screw 41 which is threaded in the plunger 38 in the threaded bore 48 so that when it is rotated fthe sliding-plunger-49 is moved into the chamber 5% whichisfilled with metalic shot 5| or the like. 'The various abutment plungers 49 are arranged to slide radially in the locking plunger "38 and have their inner ends projecting into the chamber 50 to be engaged by the shot 5|. Thus "as the locking screw 41 is tightened to force the zplunger'M-to theright,-Fig. V,-to-compress the shot -'5 the "abutment plungers-Ml will be moved 'radially outward until each :one of them firmly -engages 't'h abutment bore 4| inthe member-2 'andeaftereachpf-these plungers 4 have firmly engaged itself 'with this-bore, Y the -final tightening of the screw "41 causes this shot-to back-up be- -hind these plungers -to form a solid abutment preventing theirfurther movement so-that there can be no relative Y movement-between the link =6 and the entire workengaging link: assemblyand the member 2- of the chuck body. Withthis-particular (arrangement a 'locking device which is 'self-equalizing and which does not-tend-to cause "distortion inthe workpiece as originally clamped up the work engaging a mechanism is provided. Also "this -"arrangement provides a fixed positive lock for the work engaging assembly -after'the final equalizing -andclamping of the chucking 'device on: the work is'accompIisI-Ied. Itcan thus be seen that" since 1 the -1ocki-ngdevice. -j=ust described vpreventsall relative movement between the link -G "-and"the= chuck body 2 in any radial direction relative-to the-axis of the looking plunger 38 and since'the link H t-prevents' any= rotation of the work-engaging-:link -assembly-about the axisof the plunger- 38 and --abutment I bore -4 -this-link assembly of this chuck device will therefore --positively hold the -rough irregular pre-ldcated workpiece W in the chuck i rigidly aduring -the turning operations. iNoting -particularly-Fig. II, when thei link assembly. isvendisengaged from :thework i by first removingtheplunger from -the position 'shown in Fig. *V? to that shown in -Fig. III and then? un- -lockingthe screw 30 remove theuplunge'r 28 from" engagement "with -:the work and '-swinging link 1 out of the-latchi pocket 31"of link 6; the chuck will-assunie a position shown in Fig. II. When :in' this) position" the; chuck is prepared. for loading and unloading *of the 'work piece -W, In" order to facilitater-properlyfpositioning: the work ngagingassmbly of the links without'ainy manuali-assis'tance, v a spring urged plunger -=52 carried in the-"segmental piece 2 normally-is uiged radially inward: of the "chuck to 'engage' the link to" cause"additional -relativeiy light contact. of the abutment 2 of the'link'|-0-andrabutment-21 of the 'link 6 the work" piece W whenm "pre-located position in the chucking "device. A 's'p'ring urgedplunger fl carried in the link-'10 and engaging the bore'3 of thering gear serves to'engage the"abutments -'22arid 23'-of' the link ill. with the' 'w'orkrpiece when it 'is' :pre-located inwthe chuckiiig device. "Al'sd atensiorr spring-54 connected to a pin 55 fixed in the link 6 and con- 7 nected to. a pin'56 fixed in the ring gear I serves ,to, balance theweight'of this link to facilitate :swinging it to bring the abutments Hand 28 into initial engagement with the work W. .The

purpose oi-this arrangement is to prevent .the chucking assembly from. dropping down too far away from the work for proper and easy engagement of the mechanism with the work W and to release excessive weight from the work piece when the assembly is clamped about it before the locking device is brought into efiect whichweight might otherwise cause a deflection of the shaft downwardly from its true pre-located position if this precaution were not taken.

, We thus have a chucking device which is adaptable to engaging a pre-located work piece at a plurality 'OfIpOiDtS on its rough irregular work surface in such a way as to provide a clamping device which will not slip on such work surfaces because of its multiplicity of points which may be brought ;into active play simultaneously on the work piece, and then to provide a means whereby this work engaging assembly is positively and securely locked to; the chucking device or work spindle upon which it is mounted so that the work may be positively and rigidly held against all distortion or movement during such operations which may be performed on it.

Having thus fully set forth and described our invention in what we claim as new and designed to secure by United States Letters Patent is:

1. In a chuck, a rotary chuck body, a link pivotally mounted on said body, a pair of links pivotally mounted on the outer end of said first mentioned link, two integral and one adjustable work engaging abutments on one of said last mentioned links, a link pivotally mounted to the outer end of the link with the work engaging abutments, a link pivotally mounted to the outer end of the other of said pair of links, a pair of integral work engaging abutments on this last mentioned link, a latch link pivotally mounted on the outer end of this last mentioned link arranged to be latched with a clamping link pivotally mounted on the link connected to the link having the two integral and one adjustable abutments, and means movable in said clamping link to engage a work piece in the chuck to cause engagement of all of said abutments with said work piece.

2. In a chuck, a rotary chuck body, a link pivotally mounted on said body, a pair of links pivotally mounted on the outer end of said first mentioned link, two integral and one adjustable work engaging abutments on one of said last mentioned links, a link pivotally mounted to the outer end of the link with the work engaging abutments, a link pivotally mounted to the outer end of the other of said pair of links, a pair of integral work engaging abutments on this last mentioned link, a latch link pivotally mounted on the outer end of this last mentioned link arranged to be latched with a clamping link pivotally mounted on the link connected to the link having the two integral and one adjustable abutments, means movable in said clamping link to engage a work piece in the chuck to cause engagement or all of said abutments with said work piece, and means for locking said clamping link to said chuck body when said abutments are so engaged with the work.

3. In a chuck, a chuck body, means floatingly mounted in the chuck body to engage a work piece in the chuck, and means for locking said means to the chuck body when engaged with the workccomprising-a locking plunger movable in isaid work engaging means for movement into an abutment bore in said chuck body, radially movable'abutment plungers in said locking plunger arranged to engage said abutment bore and having their inner ends projecting into a chamber in said locking plunger, shot in said chamber, and means in said locking plunger to exert pressure on said shot to force said abutmentplungers into engagement with said abutment bore and to rigidly hold said plungers in engaged position with said abutment bore without causing relative movement between said work engaging means and said chuckbody.

4. In a chuck, a chuck body, means floatingly mounted inthe chuck body piece in thechuck, and means for locking said means to the chuck body when engaged with the work comp-rising a member carried by said work engaging means in an abutment bore in said chuck body, radially movable abutment plungers in said member arranged to engage said abutment bore and having their inner ends projecting into a chamber in said member, shot in said chamengaging means in an abutment bore in said chuck body, radially movable abutment plungers in said member arranged to engage said abutment bore and having their inner ends projecting into a chamber in said member, shot in said chamber, means in said member to exert pressure on said shot to force said abutment plungers into engagement with said abutment bore and to rigidly hold said plungers in engaged position with said abutment bore without causing relative movement between said work engaging means and said chuck body, and means to prevent rotation of said work engaging means about said abutment bore.

6. In a chuck, a chuck body, means floatingly mounted in the chuck body to engage a work piece in the chuck, and means for locking said means 7 to the chuck body when engaged with the Work comprising a member carried by said work engaging means in an abutment bore in said chuck body, radially movable abutment plungers in said member arranged to engage said abutment bore and having their inner ends projecting into a chamber in said member, shot in said chamber, means in said member to exert pressure on' said shot to force said abutment plungers into engagement with said abutment bore and to rigidly hold said plungers in engaged position with said abutment bore without causing relative movement between said work engaging means and said chuck body, and means in connection with said floating mounting to prevent rotation of said work engaging means about said abutment bore.

'7. In a work holder for a rotatable machine tool spindle, a work engaging member floatingly mounted on said spindle for engagement with a work piece prelocated on the axis of rotation of said spindle comprising, a series of links to form to engage a work work piece ,pre-located on .the :axis 'of rotation of said spindle comprising, a :series'of links to "form a chain, :means for wrapping :saidzmember about a work piece .in said chuck, means :for tightening said member around the periphery of said work piece, and .meansfor rigidly .f-as -tening said member to said ;spindle when en- ;gaged about said work piece to .rigidlyFsupport said work;piece on :said axis of;rotation of :said spindle.

19. In a work holder for a 'rotatab'letmachine tool spindle, a work engaging member floatingly mounted on said spindle ,for 4 engagement with; a work piece pre-locatedon the axisofrrotationof ,saidspindle comprising, a plurality of interconnected linksfloatingly mountedonsaid spindle, a plurality of work engaging abutments on ,said links, means for tightening said .links to .-engage said iabutments around :a ipre-zlocated workpiece ionzthei axisoferotationrofrsaid spindle, and means :for locking; said links rigidly ;on.=said work: spindle when :said links are :ztightened around said work "5 apieceffo'r :rigidly:supportingsaid work piece on :said :axis of :rotation "of said spindle.

210. In a work holder for a rotatable machine -tool1spindle, a work engaging member fioatingly mountedton said spindle r'for engagement with'a 10 "work piece :pre-located on'the-axis of rotation of said spindle comprising, :ailink pivotally mounted .on said work :spindle, a pair of links pivotally zmountedoncthe outerend of: said ffirst mentioned -link,-.a-link pivotally mounted-on the outer ends 1115 of eachofrsaid'second mentioned links, andstill -other 1inks pivotallymountedon the outer ends ofzsaidcthird mentioned'links, means "for latching .said' last: mentioned links together when said links -arezwrapped arou1id a work piece pre-located on 9,0 rthe axiso'f rotation of said spindle, means for tightening said links against said work piece, an'd means for rigidly fastening said links to said 'workspindle when tightened on said work piece.

F. GROENE. WALTER R. MEYER. 

